|
|
||||||||
The Copenhagen Muscle Research Centre, Department H, Bispebjerg Hospital, University of Copenhagen, Copenhagen DK-2200, Denmark
Normally, caffeine ingestion results in a wide spectrum of neural and hormonal responses, making it difficult to evaluate which are critical regulatory factors. We examined the responses to caffeine (6 mg/kg) ingestion in a group of spinal cord-injured subjects [7 tetraplegic (C5-7) and 2 paraplegic (T4) subjects] at rest and during functional electrical stimulation of their paralyzed limbs to the point of fatigue. Plasma insulin did not change, caffeine had no effect on plasma epinephrine, and there was a slight increase (P < 0.05) in norepinephrine after 15 min of exercise. Nevertheless, serum free fatty acids were increased (P < 0.05) after caffeine ingestion after 60 min of rest and throughout the first 15 min of exercise, but the respiratory exchange ratio was not affected. The exercise time was increased (P < 0.05) by 6% or 1.26 ± 0.57 min. These data suggest that caffeine had direct effects on both the adipose tissue and the active muscle. It is proposed that the ergogenic action of caffeine is occurring, at least in part, by a direct action of the drug on muscle.
norepinephrine; epinephrine; functional electrical stimulation; metabolic regulation; insulin; free fatty acids; glucose; lactate
This article has been cited by other articles:
![]() |
B.M. Meyers and E. Cafarelli Caffeine increases time to fatigue by maintaining force and not by altering firing rates during submaximal isometric contractions J Appl Physiol, September 1, 2005; 99(3): 1056 - 1063. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Hespel, B. O. 't Eijnde, and M. Van Leemputte Opposite actions of caffeine and creatine on muscle relaxation time in humans J Appl Physiol, February 1, 2002; 92(2): 513 - 518. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Greer, R. Hudson, R. Ross, and T. Graham Caffeine Ingestion Decreases Glucose Disposal During a Hyperinsulinemic-Euglycemic Clamp in Sedentary Humans Diabetes, October 1, 2001; 50(10): 2349 - 2354. [Abstract] [Full Text] |
||||
![]() |
M. Tarnopolsky and C. Cupido Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine consumers J Appl Physiol, November 1, 2000; 89(5): 1719 - 1724. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Greer, D. Friars, and T. E. Graham Comparison of caffeine and theophylline ingestion: exercise metabolism and endurance J Appl Physiol, November 1, 2000; 89(5): 1837 - 1844. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. E. Graham, E. Hibbert, and P. Sathasivam Metabolic and exercise endurance effects of coffee and caffeine ingestion J Appl Physiol, September 1, 1998; 85(3): 883 - 889. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |